2003 gmc motor and tranny gets hot under load. 30 0degrees. plety of water new filters fun runs all the time . any suggestions

 

wrong place for this isn't it? i asume you mean fan runs all the time? there are a few things to check first off if your fan is running non stop it has a siezed clutch and that will heat your motor up, mine did when it siezed. another thing to check is how clean the radiator, intercooler, trans cooler is. could just be very dirty and need a cleaning.
anything in front of them behind the grill, or in front for that matter?
is it possible that the water pump is bad, they are infamous for going bad on these.

 

where should this be? thanks for the reply will check all these things.

 

In the duramax forum

Sent from my DROIDX

 

this also happened to me because i am just ignoring rust building up on my radiator. it cost me lots of money just to get my gmc back on the road again. so now i do radiator flushing every 2 month sometime less because i am an everyday driver. it is the best way to protect you expensive gmc engine parts. also check for leaks in your radiator. always use the coolant from your dealer.

 

If you use proper GM dexcool you shouldn't hardly have to change your coolant, once every few years....